The specific aims of this proposal are (1) to develop a shared EPR instrumentation facility at the Oregon Health Sciences University to be used by faculty of the Oregon Graduate Center and Portland State University, and (2) to apply the facility to the study of biomedical research problems of substantial importance and interest. These problems include: (1) an EPR characterization of the resolved, native subunits of beef heart cytochorme c oxidase (Mason), (2) an EPR study of the process of reconstitution of active enzyme from isolated subunits, and the identification of the structures which give rise to the known EPR signals of the native enzyme (Mason), (3) EPR studies of oxidative disinfection mechanisms occurring in phagocytosing leukocytes (Hurst), (4) EPR studies of heme-copper ions as models for cytochrome c oxidase (Hurst), (5) comparative physical biochemistry of the binuclear iron active sties of ribonucleotide reductase and hemerythrin (Leohr, T.), (6) EPR studies of metal ion substitutions in ribonucleotide reductase, (7) metal ion substitutions in hemerythrin (Loehr, T.), (8) identification and characterization of the non-heme iron center in the enzyme, 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) synthase (Sanders-Loehr), (9) siderophore mediated iron uptake in microorganisms (Sanders-Loehr). The long term objectives of the proposal are to develop a broad understanding of oxidase and oxygenases in terms of structues and functions of oxygen-activating and oxygen-transporting proteins involved in fundamental life processes.